Show Posts
Pages: [1] 2
1  Using Arduino / Installation & Troubleshooting / Re: Windows 8 driver install "missing hash file" on: May 10, 2013, 02:58:11 am
I found the solution:

disable windows driver signing... go look at youtube for a how to.
2  Using Arduino / Installation & Troubleshooting / Windows 8 driver install "missing hash file" on: May 10, 2013, 02:43:52 am
I am trying to install the ftdi drivers, but the device manager returns the error:
" The hash for the file is not present in the specified catalog file. the file is likely corrupt or the victim of tampering".

I have tried previous versions too with no success.

any ideas?
3  Using Arduino / Project Guidance / Re: pid temperature controller on: March 22, 2013, 06:19:35 am
Start with P control.
Switch the fan fully on when the temperature goes above the SV and fully off when it goes below.
You could also use a resistor or a power transistor as a heater.

Then introduce a region around the set value in which the controller looks at the integral of the last <time in seconds> of error and decides how much to heat or cool depending on that result (fan faster or slower or heater current). Outside of this region (called proportional band), proportional control is active and the fan goes fully on or fully off.

derivative action looks at the current gradient of the change in temperature and would attempt to slow the cooling before the process variable(actual temperature) drops below the set value. or vice versa.
4  Using Arduino / Storage / Re: SD card reading problem on: March 14, 2013, 09:25:17 am
Does someone need to tell you to reformat it?

Try fat16 and fat32.
5  Using Arduino / Project Guidance / Re: IR location with beacon on: March 14, 2013, 05:48:26 am
Yea, using LED's as sensors by measuring  capacitance requires some switching and measuring of discharge times which could become troublesome if one or more of the LED's is receiving no light. Better to amplify the voltage change created across the PN junction when light hits it.

IR LEDs work at 850 to 950nm this is Near-infrared.

The LED emits light in this range, but other wavelengths will affect the PN junction in the diode to a lesser degree. so it may respond to radiation in the micrometer range.

IR sensors (that look like LED's) usually have a dark plastic casing that filters out everything except the IR in the range they want to measure.
Whereas the IR LED's usually have clear casing.
6  Using Arduino / Project Guidance / Re: IR location with beacon on: March 14, 2013, 03:34:50 am
No at the sorts of IR wavelength we are talking about here it is not affected by environment heat.
If he were to use IR LED's as I suggested they would respond to heat, and also to Red light.
7  Using Arduino / Project Guidance / Re: IR location with beacon on: March 14, 2013, 01:50:35 am
IR LED's respond quite well to variance in light levels. And they are cheap so you could mount quite a few, although reading LED sensor data with an arduino requires either 2 digital pins per LED or 1 analog pin per LED.

There are two ways to use the LED as a sensor; capacitively, or with an amplifier. --->google<---.

As Terry suggested you would need to mount each LED inside a tube to control were it receives its light from.

I would think a black tube would be a bad idea since IR is basically heat and black would absorb heat from the environment (light), and skew the sensor data as the tube heats up. Use a white tube.

8  Using Arduino / Project Guidance / Re: 5us delay when shifting digital OUTPUT levels on: March 14, 2013, 01:41:18 am
not really, its only 1 byte anyway. (only using 5 of the bits).
9  Using Arduino / Project Guidance / Re: 5us delay when shifting digital OUTPUT levels on: March 11, 2013, 05:30:41 am
Meh, since i am trying to multiplex 5 RS232 lines at 9600 baud, the arduino cannot achieve a sample rate high enough (since the arduino to arduino serial comms would need to be > 115.2kbaud).

Thus i must conclude that this is impossible with a clock frequency of only 16MHz.

Next question. How high can i clock the atmega328 before it explodes? smiley-grin
More technically, how much does its heat production increases with increased clock frequency.
10  Using Arduino / Project Guidance / Re: 5us delay when shifting digital OUTPUT levels on: March 11, 2013, 04:52:43 am
Hi guys, thanks for the helpful hints.
Yes it is definitely being caused by interrupt service routines in the serial library.

So, i need to somehow set up serial comms without using interrupts. o.O

Is that even possible.
The only way i can think of is to sample the Rx pin really fast and just hope i don't miss any bits -_-

Oh yes, the output level shifting delay is actually more like a 60us shift.
The 5us of jitter appears on the Tx line of outgoing serial comms.
11  Using Arduino / Project Guidance / Re: 5us delay when shifting digital OUTPUT levels on: March 07, 2013, 03:37:07 pm
By timer ISR you mean interrupt service routine?
Does the Serial communications use an interrupt method?

The interesting thing is the "jitter" as i am calling it is present even with the following code:

void loop() {

          PORTB = B11111111;


This is how i found the 3us loop repetion delay. the pin is low for 3us longer than it is high.

the signal on the oscilloscope appears to shiver, with the falling or rising edges shifting 5 us so that the high or low pulse would randomly be 15 us instead of 10 and then jump back to normal.

*edit: its not random, i just cant see the pattern since i dunno whats causing it. (seems to occur every 100us or so, but this is not constant).
12  Using Arduino / Project Guidance / Re: 5us delay when shifting digital OUTPUT levels on: March 07, 2013, 06:51:44 am
This code is a 5 channel bi-directional multiplexer that takes 5 inputs from on arduino and outputs it on a second arduino.
The intention is to place fibre optic lines on Tx and Rx and use the two arduino's to transmit the 5 RS-232 channels to and from devices mounted on a telescope. (hence the need for high speed, everything is very time critical).

The effect i am referring to can be observed at the output channels of the arduino's, or by simply switching the digital pins on a single arduino on and off at >50kHz and looking at the signal with an oscilloscope.


byte sendByte = 0;
byte receiveByte=0;
byte temp;

void setup() {
        Serial.begin(115200);     // opens serial port, sets data rate to 115200 bps

for(int p = 3; p <= 7; p++){
  pinMode(p, INPUT);}
for(int p = 8; p <= 12; p++){
  pinMode(p, OUTPUT);}

void loop() {

  sendByte = PIND>> 3; // read PORTD and shift it 3 bits to the right to drop the readings from pin 0-2.

        // check for data in the serial buffer
        if (Serial.available() > 0) {
                // read the incoming byte:
                receiveByte =;

          PORTB = receiveByte;
13  Using Arduino / Project Guidance / 5us delay when shifting digital OUTPUT levels on: March 07, 2013, 05:56:08 am
as the subject line suggests:

When attempting output digital data at high speeds I have noticed an anomaly, the pulse width randomly increases or decreases by 5us.

This occurs regardless of the code used to modify the pin levels. (digitalWrite, directly modifying the entire PORT register, using bitWrite or bitSet on the port register). Thus i am forced to conclude the delay is occurring at a hardware level between the port register and the transistors controlling the IO pins.

Upon examining the signals sent by the Serial library over Tx there appears to be a 10us shift that appears. this is extremely puzzling since the computer is still able to receive the data even at 115200 baud (pulse width 8.7us).

All of this data has been recorded independently of the 3us delay between the void loop() ending and restarting.

Any hints on enabling High speed communication over the digital pins would be appreciated. this 5us delay in level shifting interferes even at 9600baud.
14  Using Arduino / Programming Questions / Ethernet File passing. on: February 19, 2013, 04:42:09 am

I have an arduino webserver that is logging data to an external EEPROM chip. The user needs to be able to download all the logged data from the browser. thus i need to do one of the following:

-->Create a text file on the arduino and pass it to the browser for the user to download. (In this case my issue is sending a text file via ethernet).

-->Send the browser a string and have php or asp script assemble it into a .txt file for the user to download.

I am something of a novice programmer and I can't get the client side to execute the PHP or ASP code i send it using client.println commands.

I have the browser displaying the data in realtime.

Any help would be appreciated, i am sure it is a simple 2 or 3 lines of code i am missing that is needed to pass the .txt file (or a variable of type string) through the ethernet.
15  Using Arduino / Storage / Re: Change the pins used by the SD.h library on: February 14, 2013, 07:27:58 am
Hmm, It seems the SPI communications is handled by a hardware module which is connected to these pins, thus you cannot change them.

Although it is theoretically possible to switch the Ethernet shield and the SD shield on and off when the other is in use... it doesn't work with the sparkfun pro Ethernet board which I have  smiley-neutral
Pages: [1] 2